The present invention relates to speed control of an optical disc player, and in particular, to speed control thereof through a predetermined button over the panel of the optical disc player, the player""s device driver, or an input device of a computer system connected to the optical disc player.
The optical disc player, i.e. CD-ROM, DVD-ROM, CD-RW, DVD-RAM, has been a basic component to a multi-media computer system.
The U.S. Pat. Nos. 4,485,337, 4,783,774, 5,289,097, 5,246,479, and 5,345,347 disclose prior arts control system relating to the optical disc player.
Nowadays the nominal operation speed of commercial optical disc player is represented by multiples of a basic unit, X. It is well known that 1 X is equal to 150 kilo bytes per second for CD-ROM definition. The key component affecting the nominal operation speed of the disc player is the spindle motor inside the disc player. In general, at the commencement of read operation of optical disc player, the disc player is set at a predetermined maximum allowable speed. As lower read rate phenomenon due to conditions, i.e. out-of-focus, eccentric or vibration of disc, the optical disc player will automatically lower its operation speed to achieve a higher read rate. In addition, for some discs having specific data format, the optical disc player will set a speed specifically corresponding to the data format of disc to achieve a maximum read rate. The well known data format types include CD-Audio disclosed by Red Book, CD-ROM Mode1, CD-ROM Mode2 disclosed by Yellow Book, CD-ROM Mode2/XA Form1, CD-ROM Mode2/XA Form2 disclosed by Green Book, Recordable Compact Disc Standard disclosed by Orange Book, etc. The types of disc data format readable to an optical disc player are stored within the firmware of the player. As the optical disc, i.e. Extended Data format, MP3, or PC-Game read by the disc player is not one of the types stored, the disc player will treat as a general data format type and reads the disc by maximum allowable speed. Under this condition, usually a software or hardware decoding approach is required in the disc player to determine and vary the speed of disc player. However, this approach is expensive and difficulty in implementation.
Due to pursue of higher operation of the disc player, noises due to wind-cutting, vibration and motor humming accompany. The noise is specially significant with respect to disc of non-standard data format running at maximum allowable speed. The noise combined with the eccentric defect associated with the optical disc may seriously jeopardize the reproduction of data, i.e. audio and video, of the disc.
The main objective of the invention is to provide a method and apparatus which may tune the speed of the spindle motor at a suitable speed under control of the user.
In the invention, the user may input his/her instruction through existing button over the panel of disc player, or the player""s device driver, a keyboard or mouse connected to the computer system. The method provided is in real-time and on-line nature.
A method for controlling speed of a spindle motor of an optical disc player is provided by the invention. The method provided accepts a control signal asserted by a user and determines whether a property within the control signal meets a predetermined criterion. If the predetermined criterion is met, the speed of the spindle motor is set to another value. The speed change involved may be in either positive or negative direction. In the preferred embodiment, duration of the control signal is selected as the parameter while making the decision.
A speed control apparatus for a spindle motor of an optical disc player is provided by the invention. The spindle motor drives an optical disc disposed within the optical disc player. The apparatus includes a logic device and a speed control device. The logic device inputs a control signal for selectively outputting a speed control signal Va based on whether duration of the control signal meets a predetermined criterion. The speed control device is responsive to the speed control signal Va for adjusting speed of the spindle motor.
The merit and details of the invention will be further understood by the following descriptions and appended drawings.